FACTORS EFFECTING HYDRATION OF CUT FLOWERS

Author:

D. J. Durkin

Abstract:
Post harvest hydration of cut flowers depends on the establishment of water continuity between the plant and the vase reservoir, a process that is regulated by the rate which air is removed from conducting tissue.
Since air movement is restricted within a single vascular element by pits and/or end walls, total vascular air depends on element length, pre-harvest water potentials, and transpiration levels between harvest and placement in water.
Thus, initial post harvest care requires the creation of conditions for rapid repair of xylem water columns.

Acidification and millipore filtration of water expedite, while inclusion of sucrose retards, the initial rehydration of cut roses.
Similarly, freshly cut May Shoesmith Chrysanthemums can be rehydrated readily in acidified filtered water but rehydration is slow and erratic if shoots dry excessively before placement into the solution.
Dry chrysanthemum stems can become rehydrated in 30 to 120 minutes if placed in DI water containing 0.1 to 0.01% V/V Tween 20 wetting agent.

A requirement for lateral water movement around embolisms as a pre-condition to air removal and rapid rehydration could account for the above observations.
Apparently, lateral movement of water is slow in woody tissues, and particularly slow in woody tissues which have become desiccated.
Wetting agents lower the surface tension of water, increasing lateral water flux which expedites air removal and the re-establishment of continuous xylem water columns.

These results suggest that cut flowers should initially be handled in a manner favoring rapid rehydration, perhaps by the incorporation of a wetting agent into the solution.
Once the flower shoots regain turgor, transfer can be made to a preservative for flower development.